1. Technical Field of the Invention
This invention relates to radio telecommunication systems and, more particularly, to a system and method of fraud prevention by automatically barring calls originating from a mobile telephone upon the expiration of a predetermined time period.
2. Description of Related Art
Fraudulent use of mobile telephones in radio telecommunications networks is a serious problem. Fraudulent users may read the mobile identification number (MIN) and electronic serial number (ESN) from a legitimate subscriber's transmissions, and program that MIN and ESN into other telephones. The telecommunications network is unable to differentiate between call originations from the legitimate subscriber and the fraudulent users who are utilizing the same MIN and ESN. Therefore, the legitimate subscriber may be billed for the fraudulent usage.
Existing cellular telephone networks utilize a process known as Code Controlled Barring (CCB) to help prevent fraud. When utilizing CCB, if a mobile subscriber knows that he will not be utilizing his mobile telephone for an extended period of time, the subscriber enters a personal identification number (PIN), and thereafter, the operator denies access to the network to any mobile telephone with the MIN and ESN of the subscriber's telephone. At a later time, the subscriber may re-enter his PIN to reactivate his network access.
A problem with this solution is that the subscriber must remember to enter the PIN and bar his telephone whenever the subscriber anticipates that he will not use the telephone for an extended period. This is a burdensome inconvenience to the legitimate subscriber. In addition, subscribers often forget to bar their telephones because of other priorities. Therefore, fraudulent users often have extended periods in which they may operate with stolen MINs and ESNs before the fraud is discovered.
Although there are no known prior art teachings of a solution to the aforementioned deficiency and shortcoming such as that disclosed herein several references discuss subject matter that bears some relation to matters discussed herein. U.S. Pat. No. 4,955,049 to Ghisler discloses a method of supervising subscribers in a mobile telephone system to detect fraudulent use of a mobile telephone. Ghisler assigns a predetermined sequence of numbers to each mobile telephone in the system. When a call is made by a legitimate subscriber, the sequence number is recorded in the MSC. If the next call from a mobile telephone with the same MIN and ESN does not include the next number in the assigned sequence, the call is barred.
A disadvantage of Ghisler, however, is that every mobile telephone in the system must be programmed with a different sequence of numbers. This is an expensive and burdensome process which may not be possible to implement in existing telephones already in the field. Additionally, the MSC must be programmed with the sequences of every mobile telephone in the system, thereby utilizing valuable data processing resources.
U.S. Pat. No. 5,335,265 to Cooper et al. discloses an apparatus for preventing subscriber number cloning by discerning temporal and spatial anomalies in the use of subscriber numbers in a cellular telephone system. If two successive calls from a particular subscriber number are detected in a time interval that is too short to justify the geographical separation of the subscriber unit for the two calls, then the Cooper apparatus determines that one of the calls is fraudulent.
The Cooper apparatus, however, does not detect any fraudulent usage if the fraudulent user is not geographically separated from the legitimate user in a time period too short to account for this movement. In addition, Cooper does not identify which call is fraudulent, only that one of the two calls may be fraudulent. An extensive verification system requiring additional intersystem signaling must also be implemented.
Review of each of the foregoing references reveals no disclosure or suggestion of a system or method such as that described and claimed herein.
In order to overcome the disadvantage of existing solutions, it would be advantageous to have a system and method of automatically barring a mobile telephone from originating calls if the mobile telephone does not originate any calls within a predetermined time period. The present invention provides such a system and method.